Farm Animal Welfare

Sheep Parasite Resistance Breeding

Genetic selection for internal parasite resistance in sheep offers a sustainable welfare improvement reducing worm burden without increasing reliance on anthelmintic drugs.

Key Facts

Internal parasites cause significant production losses and welfare costs in sheep globally
Anthelmintic resistance is developing in Haemonchus contortus and other key species
Heritability of parasite resistance is sufficient for meaningful genetic selection progress
Estimated Breeding Values for faecal egg count are available in some breed societies
Parasite-resistant flocks require fewer treatments, reducing drug costs and resistance pressure

Welfare Considerations

Heavy worm burdens cause anaemia, weight loss, lethargy, and in severe cases death. Genetic selection for resistance offers a durable welfare improvement that reduces suffering while simultaneously reducing dependence on drugs whose efficacy is declining.

What You Can Do

Source breeding animals with favourable Estimated Breeding Values for parasite resistance
Implement FAMACHA scoring to identify and target treatment to most burdened animals
Support research and data collection to expand parasite resistance breeding programmes